Chemical container for high-pure chemicals

ABSTRACT

Chemical container made of plastics, comprising a body having side walls being arranged perpendicularly with respect to each other and a base, whereby at least one mold separation seam or accumulation of material due to production, respectively, is arranged in the edge being formed between two side walls and at least one mold separation seam or a combination of material due to production, respectively, is arranged diagonally over the base.

The present invention relates to a chemical container for storing high-pure liquid chemicals. Such kind of chemical containers is often made in the shape of a bottles with a handle by extrusion blowing of high-dense polyethylene (PE-HD). Those container generally comprise a round bottle-like shape or an edged bottle-like shape having plane side walls.

Among others a bottle of the latter type is made out of high-pure PE-HD, preferably of the type Lupolen 6021D or 5021D by extrusion blowing. Substantially, the bottle is assembled of two halves such that a mold separation seam runs from the base up to the opening in two of the plane side walls. The mold separation seam continues in the base area of the container.

However, bottles made of high-pure PD-HD are sensitive for cracks arising from tension in the material of the container. Those tensions particularly arise if the vapor pressure of the chemical in a closed container increases for example by an increased temperature. Particularly, the plane side walls as well as the base of the bottle are then subjected to an increased stress as a high vapor pressure in the interior of the bottle results in that the side walls and the base are deformed. The vapor pressure deforms the bottle into a shape of a sphere because of the tendency of the vapor of the chemical to maximize its volume. Particularly, the mold separation seam arranged in the plane side walls between the parts of the bottle are susceptible to cracks which may particularly arise with an overpressure in the bottle which is maintained for a longer period.

This shortcoming may be reduced by the use of bottles comprising a round shape. However, in the case of bottles having a round shape significant space is lost between bottles stacked next to each other if the bottles are for example arranged on pallets in larger groups for storing or for transport purposes.

A further possibility to overcome the shortcomings of the bottles in prior art consists in making the containers more stable by the use of larger wall thicknesses. However, a corresponding container comprises a higher weight and are more expensive in production.

Thus, it is the object of the present invention to provide a chemical container being resistant against cracks due to tension, which nonetheless has little weight and which can be produced at low cost.

This object is achieved by a chemical container according to claim 1. Advantageous embodiments of the inventive chemical container are given in the dependent claims.

Thus, the invention relates to a chemical container made of plastics comprising a body having side walls, which are perpendicularly arranged with respect to each other, and a base, whereby at least one mold separation seam or an accumulation of plastic materials due to the production, respectively, is arranged in the edge of the chemical container being formed between two side walls. Moreover, at least one further mold separation seam is arranged in the base of the chemical container diagonally over the base.

By the arrangement according to the invention of at least one mold separation seam being necessary for the production of the chemical container, consisting of several extruded parts, in an edge of the container the danger of cracks in the mold separation seam is significantly reduced. As no mold separation seams are present in the preferably plane side walls, the side walls comprise a uniform distribution of material. Even with increased vapor pressure and in case of a deformation they remain to the greatest possible extend free of tension. Constructively the edges of the container are more stable than the side walls and may not be deformed easily by an increased vapor pressure. Therefore, the danger of an occurrence of cracks in a mold separation seam being arranged there is significantly reduced.

According to a preferred embodiment the chemical container is made of high-dense polyethylene (PD-HD), preferably of the type Lupolen 6021D or Lupolen 5021D. Those materials have proven to be particularly adapted for a storage of high-pure chemicals as only very little particles are solved out of the material and can get into the chemical even during very long contact with the chemicals or long storage periods, respectively. Preferably, the chemical containers according to the invention comprise a wall thickness of 1,5-3 mm.

According to a further preferred embodiment two side walls of the chemical container are each formed in their upper section such that a partial area of the side wall is oriented obliquely backwards out of the plane of the respective side wall. Those partial areas of the two side walls running obliquely backwards into opposite directions and towards each other form an area of the chemical container, which in its completed state, is oriented substantially perpendicular with respect to the base of the chemical container and parallel with respect to a diagonal of the base.

Preferably, a handle is arranged in front of the area such formed being attached above and below close to the area or on the same. By those partial areas of the side walls being oriented backwards in the upper part of the side walls the volume of the chemical container is reduced. However, in front of the area formed, preferably, at the connection line between the two side walls a handle can be arranged in a way that it does not protrude laterally over the side walls to which it is attached, which is substantially perpendicular in the lower part of the chemical container. Therefore, the chemical container can be stacked together with further containers of the same kind without being hindered by their handles.

According to a further embodiment the elongated or bar-like handle is arranged symmetrically with respect to the edge being formed between the side walls of the chemical container and in front of the area being formed by the partial areas of the side walls.

According to yet another preferred embodiment the handle is arranged such that it does not protrude over the base in a direction parallel to the cross section being formed through the base of the chemical container.

According to another preferred embodiment the chemical container comprises a handle being blown during the production process of the parts of the container. This manner of production is particularly economic as no further step is necessary for attaching the handle.

Further features, advantages and possibilities of use of the present invention will result from the attached drawing, in which:

FIG. 1 a shows a side view of the inventive chemical container,

FIG. 1 b shows a further side view of the inventive chemical container in a position in which the chemical container is turned around 90° compared to FIG. 1,

FIG. 1 c shows a top view of the inventive chemical container,

FIG. 1 d shows a view from the bottom of the chemical container,

FIG. 2 shows a cross section through a handle of the chemical container according to FIG. 1 b along the line A-A,

FIG. 3 a, b, c, and d show a further embodiment of the inventive chemical container, and

FIG. 4 show two cross sectional views along the lines A-B and C-D of FIG. 3 b.

The chemical container shown in FIG. 1 a to 1 d comprises a substantially symmetric body 1 having the shape of a bottle consisting of four side walls 1 a-1 d being arranged substantially perpendicular with respect to each other and a base 4. In the upper part of the container the side walls end up in an opening 8 of the chemical container. Below the opening 8 the container comprises a cylindrical section being provided with a thread. A container may preferably be closed with a commercial closure according to the utility model G 91 02 564.8.

Two side walls 1 a, 1 b comprise in their upper parts partial areas 2 a and 2 b being oriented obliquely backwards with respect to the plane of the side walls 1 a, 1 b and in opposite directions towards each other. In a completed state of the chemical container those two partial areas 2 a, 2 b are connected with each other and form an area 5 being oriented substantially perpendicular with respect to the base 4 like the side walls 1 a-1 d. This can be recognized clearly in FIG. 1 b. As it is shown in FIG. 1 c the area 5 is slightly curved, however, runs substantially parallel with respect to a diagonal line of the base 4 of the container. On the bottom of the base 4 a mold separation seam 7 due to the production process is arranged. The mold separation seam 7 runs diagonally over the base 4 between two edges of the same. The mold separation seam 7 continues up to the container opening 8 in the opposite edges formed between two side walls.

As the mold separation seams are not located in the plane side walls 1 a-1 d of the chemical container, the side walls 1 a-1 d comprise a homogeneous distribution of material and are more resistant against cracks, particularly during a longer overpressure and contact of the chemical container with aggressive chemicals. The mold separation seams are arranged in the edges between the side walls. As the side walls 1 a-1 d are connected there under an angle the chemical container is more stable in those edges for reasons of their construction against deformations than the side walls 1 a-1 d. There, significantly smaller forces are exerted on the mold separation seams 3 by an increased vapor pressure in the interior of the chemical container than in the side walls 1 a-1 d.

Also the arrangement of the mold separation seam 3 on a diagonal of the base 4 of the chemical container has the advantage that this mold separation seam 7 is less subjected to cracks due to tension as the base 4 is stabilized by the edges through which runs the diagonal line. Therefore, smaller forces are exerted on a mold separation seam 7 being arranged in the diagonal by the vapor pressure than on a mold separation seam 7 being oriented parallel to the edges of base 4. The mold separation seam 7 being formed in the base 4 is obtained by squeezing of the extrusion blowing tube during the production of the chemical container.

Furthermore the chemical container preferably comprises a blown handle 6. The handle 6 is arranged in front of the area 5 being formed by the partial areas 2 a, 2 b of the side walls 1 a, 1 b and is attached to the container on top and below at the area 5. The handle 6 is also preferably assembled of two parts being separated by the mold separation seam 3. As can be taken from FIG. 1 b, the handle 6 is preferably oriented substantially in the direction of the edges being formed between the side walls 1 a-1 d. Preferably, the handle comprises a dimension and a distance between the area 5 and the handle is designed in a way, respectively, that the chemical container is adapted for being carried with gloves. This is necessary since in plenty fields of applications such as in the semiconductor production the chemical containers are carried and emptied with gloves. In order to simplify the production process the handle 6 and the halves of the bottle, respectively, are preferably formed in the same extrusion blowing process. However, also containers of the described kind are conceivable being produced without a handle 6. In this case also the partial areas 2 a, 2 b being oriented obliquely backwards may be omitted. The chemical container then comprises a larger volume. The handle could also be fixed to the chemical container at its top e.g. on two sides next to the container opening 8.

FIG. 2 shows a cross section along the line A-A of the handle 6. The handle 6 preferably comprises a T-shaped profile. Thereby, the handle 6 obtains a particularly enlarged stability and furthermore the danger of a slipping-off of the hand is reduced.

FIG. 3 a-3 d and 4 a, 4 b show a further embodiment of the inventive chemical container. This embodiment distinguishes from the first embodiment with respect to the construction of the handle 6. Parts being identical to parts in FIG. 1 a-1 d and 2 are denoted with the same reference numerals. In the present embodiment a handle 6 comprises a substantially cylindrical body being fixed to the chemical container by thin webs at the top and at the bottom.

FIG. 4 a and 4 b each show a cross section of the web being situated at the top and at the bottom, respectively. The top web comprises a T-shaped profile and the lower web comprises substantially a flat profile being provided with rips.

The chemical containers described are adapted for the reception of high-pure chemicals like e.g. hydrofluoric acid (HF), hydrochloric acid, sulfuric acid, hydrogen peroxide, ammonium fluoride solutions, etching mixtures of HF and ammonia solution, ammonia solution, ethanoic acid, 2-propyl alcohol, phosphoric acid, and nitric acid.

Preferably all parts of the chemical container including the thread and handle 6 are made of the same material, preferably of high-pure PE-HD, preferably of the type lupolen 6021D or 5021D by extrusion blowing.

REFERENCE NUMERALS

(1) body

(1 a-1 d) side wall

(2) a, b partial area

(3) mold separation seam

(4) base

(5) area

(6) handle

(7) mold separation seam in the base

(8) container opening 

1. Chemical container made of plastics, comprising: a body (1) having side walls (1 a, 1 b, 1 c, 1 d) being arranged perpendicularly with respect to each other and a base (4), whereby at least one mold separation seam (3) or accumulation of material due to production, respectively, is arranged in the edge being formed between two side walls (1 a, 1 b) and at least one mold separation seam 7 or a combination of material due to production, respectively, is arranged diagonally over the base
 4. 2. Chemical container according to claim 1, the chemical container being made of high-dense polyethylene (PD-HD), preferably of the type Lupolen 6021D or Lupolen 5021D.
 3. Chemical container according to one of the preceding claims, whereby two side walls (1 a, 1 b) of the chemical container being each formed in their top section such that a partial area (2 a, 2 b) of the side wall (1 a, 1 b) is oriented obliquely backwards out of the plane of the respective side wall (1 a, 1 b) and the partial areas (2 a, 2 b) together form an area 5 being oriented perpendicularly with respect to the base 4 and parallel with respect to one diagonal of the base
 4. 4. Chemical container according to claim 3, whereby a handle (6) is attached at the top and at the bottom to the area (5) to the chemical container, being oriented substantially symmetrical with respect to the edges, being formed between two side walls (1 a, 1 b), respectively, of the chemical container and being arranged in front of the area (5) being formed by the partial areas (2 a, 2 b) of the side walls being obliquely arranged.
 5. Chemical container according to one of the preceding claims, whereby the handle (6) is arranged such that it does not protrude in a direction parallel with respect to the cross section area formed by the base (4) over the base (4).
 6. Chemical container according to one of the preceding claims, whereby the chemical container comprises a handle (6) being formed in one piece with the chemical container.
 7. Use of the chemical container according to one of the preceding claims for storing and for transport of the chemicals.
 8. Use according to claim 7, whereby the chemicals are selected under: hydrofluoric acid (HF), hydrochloric acid, sulfuric acid, hydrogen peroxide, ammonium fluoride solutions, etching mixtures of HF and ammonia solution, ammonia solution, ethanoic acid, 2-propyl alcohol phosphoric acid, and nitric acid. 